This invention relates to a movement amount estimation system for estimating a movement amount of a holder of a mobile terminal, in particular, a movement amount estimation system for estimating a movement amount based on acceleration data measured by an acceleration sensor included in the mobile terminal.
As a result of the drastic development of portable information terminals as represented by smartphones, the markets of location-based services for specifying location information of a holder of the terminal have been expanding.
As the location-based services, there exist a service for collecting previous movement loci of a terminal to provide marketing based on the location to which the terminal holder has moved and a service for associating the movement loci and various types of sensor data with each other to provide a wide range of sensing.
In general, the location information of the holder of the terminal is calculated by reception of a global positioning system (GPS) signal by the terminal. Various positioning methods, which enable positioning of the location of the terminal even in the case where the holder of the terminal is located indoor where the terminal cannot receive the GPS signal, have been established. The positioning methods include an environmental positioning method and an autonomous positioning method. The environmental positioning method involves the installation of positioning equipment on an environment side, whereas the autonomous positioning method does not involve the installation of positioning equipment on the environment side.
The positioning equipment to be installed on the environment side has not been widespread yet. Therefore, the use of the autonomous positioning method is effective, in particular, for an indoor positioning method with which a target region to be positioned extends over a wide range.
As the autonomous positioning method, there is known a technology for calculating a movement amount in a horizontal direction by using a three-axis acceleration sensor (see, for example, JP 2003-329705 A). There is also known a method for estimating a walking velocity of the holder of the terminal in the horizontal direction and a walking direction of the holder of the terminal in the horizontal direction based on data measured by the three-axis acceleration sensor, a magnetic direction sensor, and a gyro (angular velocity) sensor.
However, the movement of the holder of the terminal, who is inside of a building, includes not only the movement in the horizontal direction on the same floor but also the movement in a vertical direction between floors.
Although a method of calculating a movement amount in the vertical direction by using a barometric sensor or the like is known, the barometric sensor is not mounted in general portable information terminals. Therefore, the movement amount in the vertical direction is desired to be calculated by using an acceleration sensor, which is mounted in the general portable information terminals.